ABSTRACT Tobacco is the leading cause and alcohol is the third leading cause of preventable death and disability in the U.S. Almost one-third of all cancers are directly attributable to smoking, and alcohol increases the risk for cancers of the mouth, pharynx, larynx, esophagus, liver, colon, rectum, and breast. Moreover, the concomitant use of tobacco and alcohol synergistically increases the risk for some cancers (e.g., head and neck). Not only are tobacco and alcohol use major public health problems in their own right, they are closely linked behaviors. Smokers are much more likely to drink than are non-smokers and the prevalence of problem drinking is much higher among smokers than among nonsmokers. Unfortunately, tobacco and alcohol use are major public health problems in Puerto Rico (PR). Although the prevalence of smoking among Puerto Ricans living in PR is lower (12.5%) than in the continental U.S. (20.6%), the five leading causes of death in PR are associated with smoking (i.e., heart disease, cancer, stroke, hypertension and chronic pulmonary disease). Similarly, although Puerto Ricans are less likely to drink than is either the general population of the U.S. or Hispanics in the U.S., they are more likely to be binge drinkers if they do drink (http://www.cdc.gov/brfss/). Furthermore, the negative health consequences of alcohol and tobacco are not confined strictly to heavy or abusive use. For example, the risk for each of the alcohol-related cancers increases substantially with alcohol consumption of more than two drinks per day for men, and one drink per day for women. In fact, a landmark report from the Institute of Medicine (IOM) identified "at risk" drinking (chronic moderate to heavy levels of use, binge drinking, or drinking and driving) as a serious public health concern because it is associated with numerous other negative health and social consequences, as well as cancer. Therefore, the IOM recommended integrating screening, prevention, and treatment of at risk drinking into public health settings. Thus, a critical strategy for cancer risk reduction among Puerto Rican smokers is reducing the use of these two substances. The proposed study is a randomized clinical trial that will evaluate the efficacy of a unique, theoretically- and empirically-based "Motivation and Problem-Solving" (MAPS) approach to treating tobacco and at risk alcohol use in a population-based, public health setting. MAPS is a treatment approach that combines attributes of both motivational interviewing and cognitive behavioral/problem-solving treatment approaches. Participants are Puerto Rican smokers who are also "at risk" drinkers, and who call the Puerto Rico Quitline (PRO) for smoking cessation counseling. At risk drinking, as defined by the National Institute on Alcohol Abuse and Alcoholism, refers to a constellation of alcohol use behaviors that increase risk for physical and psychosocial problems. Our previous research among smokers calling the PRO indicates that 36% are at risk drinkers. Participants (N=200) will be randomly assigned to either a MAPS treatment with a focus on smoking cessation, or a MAPS+ condition that focuses on smoking cessation and the reduction of at risk alcohol use. Treatment is telephone-based, and designed to be easily disseminated to health care systems and other population-based settings for tobacco and alcohol control. The primary outcome variable is at risk drinking. We hypothesize that MAPS+ will reduce at risk alcohol use behaviors relative to MAPS. Although we will also examine smoking cessation as an outcome, we believe that there will be no difference between MAPS and MAPS+ with respect to smoking cessation outcomes. Although Ml and cognitive behavioral/problem-solving approaches have a relatively long history in the treatment of alcohol use and smoking cessation, to the best of our knowledge, this study would be the first to apply a motivational enhancement approach to concomitantly treating smoking and alcohol use. It is important to note that the goal of MAPS+ is not necessarily to promote abstinence from alcohol, but to modify at risk drinking behaviors. The specific aims of this project are to: 1. Evaluate MAPS and MAPS+ effects on at risk alcohol use (and smoking cessation) among Puerto Rican smokers who are also at risk drinkers. 2. Assess MAPS and MAPS+ effects on treatment mechanisms and the role of those mechanisms in mediating treatment effects on at risk drinking (and smoking cessation). 3. Evaluate the cost-effectiveness of MAPS and MAPS+ in the reduction of at risk drinking (and smoking cessation).